Renewable Energy Isn’t Free

Monday, May 25th, 2009

Ralph Ellis reminds us that renewable energy isn’t free:

Oil is not free, despite it just sitting in the ground; water is not free, despite it falling from the sky; nuclear power is not free, despite the raw materials being ridiculously cheap, and neither is any renewable energy resource ‘free’. In fact, the conversion process from ‘free’ renewable energy to usable grid electricity is remarkably expensive and its enormous costs are being subsidised by the consumer. In the UK, this subsidy is achieved through Renewables Obligation Certificates, the cost of which are eventually passed onto the consumer. In 2006 the cost to consumers was £600 million, and this is predicted to rise to £3 billion in 2020. 1 That is about £200 per household per annum, on top of current energy bills, for the privilege of using of ‘free’ energy.

His greater concern is that renewable energy is unreliable energy — or at least dangerously intermittent energy:

Perhaps the first renewable source we should discuss is tidal power. Unfortunately, while tidal power initially looks like a dream power source of cheap, renewable energy, it suffers from massive variability in supply. The energy that it produces is tidal, and the tides are, of course, linked to the orbit of the Moon, with there being about two tides every day. This sinusoidal tidal pattern produces four slack periods during each day when the tide is turning, either at high tide or at low tide, and during these slack periods the tidal power system will not generate any electricity at all. Unfortunately, the energy that is produced is therefore delivered at set periods of the day which are connected to the orbit of the Moon, rather than our daily lives, and so the electricity produced is in no way synchronised with the electrical demand cycle. If these slack periods coincide with the 7-am and 7-pm peak demands for electricity, as they will several times a month, then the whole generating system is next to useless.

Since the energy produced earlier in the day cannot be stored, as will be explained later, extra generating capacity will have to be brought on-line to cover the deficiency. This means that for every tidal system installed, a conventional power station will have to be either built or retained to ensure continuity of energy supply. But this power station will have to be up and running all the time, what is known in the industry as ’spinning-reserve’, as it takes up to 12 hours to bring a power station on-line from a cold start-up. Thus if we are to maintain continuity of supply, this wonderful ‘free-energy’ tidal source actually results in twice the cost and saves very little in the way of hydrocarbon fuels.

Wind power is even more problematic:

A report from Denmark2 indicates that the Danish ‘wind carpet’, which is the largest array of wind turbines in Europe, generated less than 1% of installed power on 54 days during 2002. That is more than one day every week of the year without electrical power. However, if we broaden the definition of ‘without power’ slightly, the same Danish ‘wind carpet’ generated less than 10% of installed capacity for some 16 weeks during 2003. Yet Denmark has the same kind of northerly, maritime weather systems as does the UK. Thus the wind-generation industry is lying to us, once more, for a ‘wind carpet’ that generates less than 10% of installed capacity it next to useless, for the national electrical grid will never cope with such a massive reduction in power supply. In fact, wind generation is so useless, that Denmark, Europe’s largest wind generating nation by far, has never used any of its wind-generated electricity — because it is too variable. It is almost impossible to integrate wind power into a normal generating grid, and so Denmark has merely exported its variable wind supplies to Norway and Sweden.3 These nations can cope with these electrical fluctuations because of their abundance of hydro-electric power, which can be turned on and off quite rapidly, unlike most other generating systems.

Solar’s obviously impractical in the UK. Of course, it’s not particularly well-suited for Germany either, but that hasn’t stopped them…

(Hat tip à mon père.)

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